You're probably used to pop-ups on websites begging you to sign-up for an email newsletter, enter a contest, or watch an ad. But tomorrow the web will be plastered in a different sort of pop-up as some the tech's biggest companies fight to maintain a free and open internet.

Last May, the Federal Communications Commission began the process of dismantling the net neutrality rules it adopted in early 2015. Without these rules, internet service providers could be free to block you from viewing particular sites, throttle the speeds of video streaming services, or charge you extra to view particular content. The end of net neutrality could make it much harder for new companies to get a toe-hold in markets such as streaming media or video calling, or even stifle free speech online.

Tomorrow, sites across the web will place alerts on their pages encouraging people to send letters to the FCC asking the agency not to jettison net neutrality. Hundreds of companies and organizations plan to participate in this so-called "Day of Action," from giants such as Amazon, Google, Facebook, and Netflix to Reddit, Etsy, PornHub, Spotify, and even some smaller internet service providers like Ting and Sonic.

The plan is reminiscent of a similar campaign in January 2012, when countless websites, including Google, Wikipedia, and WIRED, blacked out parts of their pages to raise awareness about a pair of draconian intellectual property reform bills known as SOPA and PIPA that Congress was debating at the time. The campaign worked. Voters flooded their representatives with emails, phone calls, and letters, and the two bills died an early death.

It was a crucial moment in the history of internet policy and proved that activists and web companies could mobilize the public to push back against harmful legislation, and now the organizers behind the Day of Action are hoping to repeat that success. But not every company is equally committed to the cause of net neutrality. Here's where seven internet giants stand on the issue, and what a world with fast and slow lanes might mean for them.